1. Field of the Invention
The present invention relates to head assemblies and memory devices, and particularly relates to a head assembly and a memory device, which has a head at the tip thereof, and is attached to an actuator assembly or the like.
In recent years, keeping pace with the development of an increased recording density and the miniaturization of a magnetic disk device used as a memory storage, a magnetic head assembly having a magnetic head for recording and reproducing has also been subject to miniaturization. In such miniaturization, a signal-conducting pattern is often formed on a suspension of the magnetic head assembly. Thus, a signal-conducting pattern which is protected from damage in an assembling process is needed. Also, the precision of the positioning of the magnetic head on the assembly must be improved in order to achieve a high recording density.
2. Description of the Prior Art
In magnetic disk devices of the prior art, magnetic heads are provided at one side or both sides of a predetermined number of magnetic disks. A magnetic head is mounted on the tip of a suspension, which is in turn connected to a tip of a carriage arm of an actuator. The magnetic heads are moved in a radial direction of the magnetic disks by the driving of the actuator.
FIGS. 1A and 1B show an isometric view and a cross-sectional view, respectively, of a magnetic head assembly of a magnetic disk device of the prior art. In FIG. 1A, a magnetic head assembly 11 includes a magnetic head 13 mounted on a tip of a suspension 12 which is formed by bending a metal plate made of such a material as stainless steel at a predetermined angle. The magnetic head 13, which includes a thin-film head mounted on a slider, is fixed on the suspension 12 with glue and the like. Also, an attaching hole 14 is formed at a rear end of the suspension 12.
A signal-conducting pattern 15 which conducts to four signals the magnetic head 13 for recording and reproducing is formed on the suspension 12. The signal-conducting pattern 15 is coupled at one end to nodes of the magnetic head 13. Node part 16 is formed at the other end of the signal-conducting pattern 15 for leading the signals, and is located on one side of the suspension 12.
As shown in FIG. 1B, an insulator layer 17 is formed on a base material 12a of the suspension 12, and, then, the signal-conducting pattern 15 of a four-line conductive material pattern is formed with such a material as copper by etching and the like on the insulator layer 17. Finally, a protective layer 18 is formed on the signal-conducting pattern 15 with an insulating material. This protective layer 18 covers all of the signal-conducting pattern 15 and is of a thickness on the order of several micrometers. Here, at the rear end of the suspension 12, except for the attaching hole 14 and the signal-conducting pattern 15, a metal dummy pattern 19 is formed for making a flush surface with the protective layer 18. The magnetic suspension assembly 11 thus formed is attached to an actuator.
FIG. 2 shows a plan view of an actuator. In FIG. 2, an actuator 20 includes a plurality of carriage arms 22 revolving around a rod 21 and a VCM (voice coil motor) 23 having a voice coil as a driving part. The magnetic head assembly 11 is attached to a tip 22a of the carriage arm 22 which has an attaching hole 24.
FIGS. 3A and 3B show illustrative drawings explaining the attaching of the magnetic head assembly of the prior art. In FIGS. 3A and 3B, the tip 22a of the carriage arm 22 and the suspension 12 are shown in cross section perpendicular to a longitudinal direction of the carriage arm 22 and the suspension 12. As shown in FIG. 3A, a spacer 25 is fixed to the attaching hole 14 of the suspension 12. Then, the spacer 25 is fit into the attaching hole 24 of the carriage arm 22, where one of the suspensions 12 is provided on each side of the tip 22a of the carriage arm 22. In FIG. 3A, thus, the spacers 25 fixed to the suspensions 12 are provided on both the upper side and the lower side of the tip 22a to form an assembly. In FIG. 3B, a predetermined number of the assemblies are lined up in a vertical direction.
On both sides of the line of the assemblies, clamps 26a and 26b are arranged with pressing parts 27a and 27b provided thereon. Each of the pressing parts 27a and 27b has a tapered end which comes in contact with the rear end of the suspension 12. Thus, when the clamps 26a and 26b clamp, the pressing parts 27a and 27b come in contact with each other and with the suspensions 12, so that the assemblies are pressed from both the upper side and the lower side.
Then, a ball 28 is inserted into a hole formed in the spacer 25 through the attaching hole 14 of the suspension 12 so as to press the spacer 25 from the inside of the hole. Thus, the spacer 25 is pressed from the inside to the attaching hole 24 at the tip 22a of the carriage arm 22. In this manner, the magnetic head assemblies 11 are attached to the head carriage arm 22.
When pressing the suspensions 12 against the tips 22a of the carriage arms 22 with the pressing parts 27a and 27b, the tips of the pressing parts 27a and 27b often cause damage to the suspension. That is, the tips of the pressing parts 27a and 27b often scrape and cut the protective layer 18 and the signal-conducting pattern 15 formed at the rear end of the suspension 12.
Also, when gluing the magnetic head 13 to the tip of the suspension 12, the slider is distorted by contraction of the glue when it solidifies. This distortion is not uniform so that a flying height (i.e., the gap between the slider and the magnetic disk) varies between different magnetic heads. This causes a degradation of performance in magnetic disk devices.
Accordingly, there is a need in the field of magnetic disk devices for a head assembly and a memory device which have a high yield and a high performance.